Attention-deficit/hyperactivity disorder comorbidity in a sample of veterans with posttraumatic stress disorder.

This study examined attention-deficit/hyperactivity disorder (ADHD) comorbidity in military veterans with a high prevalence of posttraumatic stress disorder (PTSD) and evaluated the relationships between the 2 disorders and exposure to traumatic events. The sample included 222 male and female military veterans who were administered structured clinical interviews based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Results show that 54.5% met the criteria for current PTSD, 11.5% of whom also met the criteria for current adult ADHD. Level of trauma exposure and ADHD severity were significant predictors of current PTSD severity. Evaluation of the underlying structure of symptoms of PTSD and ADHD using confirmatory factor analysis yielded a best-fitting measurement model that comprised 4 PTSD factors and 3 ADHD factors. Standardized estimates of the correlations among PTSD and ADHD factors suggested that the largest proportion of shared variance underlying PTSD-ADHD comorbidity is related to problems with modulating arousal levels that are common to both disorders (ie, hyperarousal and hypoarousal).